Efforts to control the regioselectivity and stereoselectivity of singlet oxygen chemistry are to continue. Preliminary results indicate that there is little understood about such processes although the effects are real. The results will subsequently be applied to specific target molecules to be derived from neutral potentially homoaromatic systems, benzoheptalenes, annulated cyclooctatetraenes, and various alicyclic compounds including steroids. The goal is to prepare isomerically pure mono- and diepoxides having structural features which appear to be suitable for triggering carcinogenic and/or oncologic activity.